<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>

        var CreateDiv = (function() {
            var instance 

            function Create (html) {
                if(instance) {
                    return instance
                }
                this.html = html;
                this.init()
                return instance = this
            }

            Create.prototype.init = function() {
                var div = document.createElement("div")
                div.innerHTML = this.html
                document.body.appendChild(div)
            }

            return Create
        })()

        var a = new CreateDiv("test1")
        var b = new CreateDiv("test2")

        console.log(a === b ,a,b);
    </script>
</body>
</html>